To be fair, anon also can’t tell the truth or if someone is making shit up.
I’d wager the vast majority of people that don’t know anything about another person’s religion couldn’t tell if what they’re saying is true or not.
Circumcision, fasting, transubstantiation, without any knowledge or frame of reference there really is no way to tell if someone is just talking out of their ass or not when it comes to religious traditions.
In my culture we sing our religious allegiance to the decapitated head bust of the great dictator who secularised the country
(not even joking)